1. Field of the Invention
The present invention relates to an image forming apparatus adapted for use for example in a copier or a printer.
2. Description of the Prior Art
The process sequence control or timing control conventionally employed for example in copiers for controlling the process effecting means (equipment required for performing the steps of charging, imagewise exposure, development, transfer, fixing etc.) has been achieved by combinations of relay circuits or so-called hard wire logic circuits.
Such relay circuits or logic circuits, being designed and structured for a particular performance, require cumbersome redesigning and rewiring if there is any change in required performance. Also such circuits, if required to control an elevated number of equipment or to perform a complex control, result in extremely complicated structure and wirings, thus deteriorating the reliability and rendering the maintenance and inspection difficult.
Though there is also known a process sequence control system in which the sequence functions are pre-programmed, the drawback in complexity of circuit composition is not still solved.